UTF7Encoding 類別

定義

public ref class UTF7Encoding : System::Text::Encoding

public class UTF7Encoding : System.Text.Encoding

[System.Serializable]
public class UTF7Encoding : System.Text.Encoding

[System.Serializable]
[System.Runtime.InteropServices.ComVisible(true)]
public class UTF7Encoding : System.Text.Encoding

type UTF7Encoding = class
    inherit Encoding

[<System.Serializable>]
type UTF7Encoding = class
    inherit Encoding

[<System.Serializable>]
[<System.Runtime.InteropServices.ComVisible(true)>]
type UTF7Encoding = class
    inherit Encoding

Public Class UTF7Encoding
Inherits Encoding

繼承

Object

Encoding

UTF7Encoding

屬性

SerializableAttribute ComVisibleAttribute

範例

以下程式碼範例示範如何使用 來 UTF7Encoding 編碼一串 Unicode 字元並將其儲存在位元組陣列中。 注意當位元組陣列解碼回字串時，資料不會遺失。

using System;
using System.Text;

class UTF7EncodingExample {
    public static void Main() {
        // Create a UTF-7 encoding.
        UTF7Encoding utf7 = new UTF7Encoding();
        
        // A Unicode string with two characters outside a 7-bit code range.
        String unicodeString =
            "This Unicode string contains two characters " +
            "with codes outside a 7-bit code range, " +
            "Pi (\u03a0) and Sigma (\u03a3).";
        Console.WriteLine("Original string:");
        Console.WriteLine(unicodeString);

        // Encode the string.
        Byte[] encodedBytes = utf7.GetBytes(unicodeString);
        Console.WriteLine();
        Console.WriteLine("Encoded bytes:");
        foreach (Byte b in encodedBytes) {
            Console.Write("[{0}]", b);
        }
        Console.WriteLine();
        
        // Decode bytes back to string.
        // Notice Pi and Sigma characters are still present.
        String decodedString = utf7.GetString(encodedBytes);
        Console.WriteLine();
        Console.WriteLine("Decoded bytes:");
        Console.WriteLine(decodedString);
    }
}

Imports System.Text
Imports Microsoft.VisualBasic.Strings

Class UTF7EncodingExample
    
    Public Shared Sub Main()
        ' Create a UTF-7 encoding.
        Dim utf7 As New UTF7Encoding()
        
        ' A Unicode string with two characters outside a 7-bit code range.
        Dim unicodeString As String = _
            "This Unicode string contains two characters " & _
            "with codes outside a 7-bit code range, " & _
            "Pi (" & ChrW(928) & ") and Sigma (" & ChrW(931) & ")."
        Console.WriteLine("Original string:")
        Console.WriteLine(unicodeString)
        
        ' Encode the string.
        Dim encodedBytes As Byte() = utf7.GetBytes(unicodeString)
        Console.WriteLine()
        Console.WriteLine("Encoded bytes:")
        Dim b As Byte
        For Each b In  encodedBytes
            Console.Write("[{0}]", b)
        Next b
        Console.WriteLine()
        
        ' Decode bytes back to string.
        ' Notice Pi and Sigma characters are still present.
        Dim decodedString As String = utf7.GetString(encodedBytes)
        Console.WriteLine()
        Console.WriteLine("Decoded bytes:")
        Console.WriteLine(decodedString)
    End Sub
End Class

備註

編碼是將一組 Unicode 字元轉換成位元組序列的程式。 解碼是將一連串編碼好的位元組轉換成一組 Unicode 字元的過程。

UTF-7 編碼將 Unicode 字元表示為 7 位元 ASCII 字元序列。 此編碼支援特定協定，通常是電子郵件或新聞群組協定。 由於 UTF-7 並不特別安全或穩健，且大多數現代系統都支援 8 位元編碼，因此通常應該優先使用 UTF-8 而非 UTF-7。

欲了解更多關於 支援的 UTF 及其他 System.Text編碼的資訊，請參閱 .NET Framework 中的字元編碼。

該 GetByteCount 方法決定編碼一組 Unicode 字元的位元組數，並 GetBytes 執行實際編碼。

同樣地，方法 GetCharCount 決定解碼一串位元組的字元數，而 和 GetCharsGetString 方法則執行實際解碼。

UTF7Encoding 對應於Windows代碼頁 65000。

另請參閱

• Decoder
• Encoder
• 理解編碼